This tool is for tightening or for the removal of the factory Smith & Wesson(R) M&P(R) 15-22 .22LR barrel nut. Smith & Wesson(R) M&P(R) 15-22 .22LR barrel nut have been known to come loose over time, now you have the tool to tighten the factory barrel nut. If you plan on swapping out the factory handguards, you may need this tool to get the factory handguards off. NcSTAR has KeyMod(R) free float handguards made specifically for the Smith & Wesson(R) M&P(R) 15-22 .22LR. Tool has machined teeth to interface with the Smith & Wesson(R) M&P(R) 15-22 .22LR factory barrel nut. Also has flats on the opposite side for a wrench to tightening or loosening the barrel nut. Tools is hollow and is designed to slide over the barrel. Black anodized finish, aluminum construction.